Chocolatier Thorntons revealed a drop in profits after sales were hit by December's snowy weather as it said trading at its stores in 2011 has been weak.

The company said December's Arctic weather wiped £3.5 million from its sales and raised the cost of manufacturing and delivering its goods by £500,000.

Thorntons, which is celebrating its 100th anniversary this year, reported that pre-tax profits declined 8.5% to £8.3 million in the 28 weeks to January 8 as it battled higher commodity prices, although revenues increased 4.8% to £133.5 million helped by strong sales to supermarkets.